From 9ca12ac04bb7d7cfb28aa549dcd3d15761f15543 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 11 Apr 2019 13:34:46 +1000 Subject: kernel/cpu: Allow non-zero CPU to be primary for suspend / kexec freeze This patch provides an arch option, ARCH_SUSPEND_NONZERO_CPU, to opt-in to allowing suspend to occur on one of the housekeeping CPUs rather than hardcoded CPU0. This will allow CPU0 to be a nohz_full CPU with a later change. It may be possible for platforms with hardware/firmware restrictions on suspend/wake effectively support this by handing off the final stage to CPU0 when kernel housekeeping is no longer required. Another option is to make housekeeping / nohz_full mask dynamic at runtime, but the complexity could not be justified at this time. Signed-off-by: Nicholas Piggin Signed-off-by: Peter Zijlstra (Intel) Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-4-npiggin@gmail.com Signed-off-by: Ingo Molnar --- kernel/power/Kconfig | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel/power') diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index f8fe57d1022e..9bbaaab14b36 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -114,6 +114,15 @@ config PM_SLEEP_SMP depends on PM_SLEEP select HOTPLUG_CPU +config PM_SLEEP_SMP_NONZERO_CPU + def_bool y + depends on PM_SLEEP_SMP + depends on ARCH_SUSPEND_NONZERO_CPU + ---help--- + If an arch can suspend (for suspend, hibernate, kexec, etc) on a + non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This + will allow nohz_full mask to include CPU0. + config PM_AUTOSLEEP bool "Opportunistic sleep" depends on PM_SLEEP -- cgit v1.2.1